How does ion lifter work

In my high school physics class, my teacher coach of , at the time, and currently coach of , Eric Stokely, had this fixation on flying cars. Oh well, one step closer. Be careful poking around in there, though. As stated on the web site, the HV power supply from an older style computer monitor or TV set should be all the power supply you need. Cut to the claustrophobic bridge, where the faint whine of fans is interrupted by the sound of the debris field hitting the hull.

Not every movie and TV show. You are right though that that it wouldn't be the same. P Firefly. BerislavLopac on Nov 21, root parent prev next [—]. I have a solid, realistic explanation why you can hear other spacecraft and explosions in movies like Star Wars! BerislavLopac on Nov 22, root parent next [—]. My idea is that it's basically a UI enhancement: sound is the best method at least for humans; but those space operas tend to be quite anthropocentric anyway to perceive environment in a 3D way.

So what we're hearing is not actual sound of explosions and ships; it's actually interpretations of their signals of various scanners, converted to sound and played in cockpit in such a way that the pilot can easily determine type and distance by the perceived location of its sound source. Hope this makes sense.

Kye on Nov 22, root parent next [—]. Makes sense. Car audio designers already create sounds in cars to make up for the lack of them. Doors don't make much sound anymore naturally, but they've been designed to keep making sound when they close.

And road noise is simulated or piped through the speakers. There's no reason that would stop with terrestrial vehicles. TheSpiceIsLife on Nov 22, root parent prev next [—]. Because there's no such thing as a perfect vacuum? Because when there's an explosion there's also an expanding medium that sounds can travel through? I suggest AR - why would ship designers neglect an entire input channel to the humans in control? I mean, it would be a hell of a benefit if you can hear a ship explode behind you while you look at the the one in front of you or at a screen If you don't have that, you're a little more limited to relying on visual information for everything.

Is it true that there's no such thing as a perfect vacuum? How much 'stuff' is in vacuum on average to make it impure? Sorry if these are stupid questions. NikolaeVarius on Nov 21, root parent next [—]. Kye on Nov 21, root parent prev next [—]. I was going to say synesthesia. I'm not sure I heard every ship I remember having sound. Shivetya on Nov 22, parent prev next [—]. Would it be all that silent at traditional airplane speeds?

Also I wonder if you ran it like the old pulse jets if it would easier to keep one aloft. That xkcd fits my daily experience on HN extemely well. SargeZT on Nov 21, parent next [—]. Basically a summary of my entire professional life. SargeZT on Nov 21, root parent next [—]. Leave me broken and just give me the six million. Hahaha mine too :'D. It feels like HN became Reddit overnight. We had a good run.

I picture the second part said in Ron Howard's "The Narrator's" voice. I imagined "the front fell off. Lots of people in the robotics field might be making such an observation. Hopefully, this won't also apply to many production self driving vehicles.

The first fully self-driving car to market will be from the company that cuts the most corners and compresses schedules the most. I'm sure it will be fine. Does this apply to self driving cars? I find engineers are generally passionate, interesting people to be around, especially if they're masters in unintentional, deadpan humour. So if this fell on someone, would it electrocute them? Depends on a lot of things.

But a big one is the amperage used. There's a parallel frequently used. Voltage is the reach, and amperage is how hard you can hit. This is why a lot of Tesla's demonstrations weren't fatal to people and being high frequency. This device, probably not using high amperage anywhere that would really matter. But they are pulling high amps from the batteries, which is then converted to high voltage.

So there is a distinct possibility that it could kill someone. But not likely in this small of a form factor. So amperage is 0. It's not necessarily fatal[0], but it's not going to be a good day either.

In general, hundreds of watts of high voltage DC is not something to take lightly. At the very least, you might accidentally fry any microelectronics on your person! Possibly even near your person due to the arcing you cause! High voltage DC has a tendency to make microelectronics nonfunctional. Voltage doesn't kill, current does. One can easily take 10s of thousands of volt across the the heart if the amperage is low, but a car battery putting out 12 volts and several amps can.

Personally, I've taken leads from a V, 3KW solar panel array from hand to hand and not felt a thing. Have so same 2 leads touch the same hand, you're going to feel it. For me, felt like a snake bite, minus the venom.

Left a few small red mark on my hand that cleared up in a few days. Mind this is all in reference to DC current. AC is another beast. Edit: it takes around, or less, than 1. At 40kV and watts, it's 15mA, so yes, it could definitely stop their heart I'm guessing not. More like an electric fence: volts are high but current is low.

When I submit a link, it doesn't show up. Does HN penalize Tor? Your submission got caught by a software filter. I've restored it, but in the future you should email us at hn ycombinator. There are too many comments for us to see most of them. A flute also doesn't have any moving parts. This is absurd and scientific american sure has taken a fall from grace in order to believe it.

Electrostatic "lifters" have been around for half a century. They are toys. They do not scale up. They cannot even lift themselves as their power supply or energy storage has to be on the ground with tiny wires going up to the lifter.

There is absolutely no chance this can be called a 'plane'. It always has to be tethered with wire to deliver the power. It's not entirely clear from the article, and I can't find the Nature publication yet It does carry it's own power supply and battery: "Finally Barrett used a computer model to get the most out of every design element in the aircraft, from the thruster and electrical system designs to the wires that ran through the plane.

We had to make hundreds of changes. Edit: found some more material. No video of the actual plane yet. But the professor has a website here. This is such a typical Hacker News dismissal. The paper isn't even on Nature's website; please give it at least a week or a read before dumping on the author.

Well this particular plane runs off a battery And from TFA sadly, the paper in Nature is referred to, but not properly cited a main innovation is the development of a system that provides the required 40, volts from a battery in a form-factor amenable to small aircraft think drone usage.

Varcht on Nov 21, root parent next [—]. Will make being a baggage handler pretty exciting. Does it? As far as I can tell it doesn't exist outside of the person's mind. Having played around with lifters myself using balsa, al foil, and a rectified neon sign transformer I just don't think the physics can work out. And there's no physical plane photos or videos to support otherwise. Until then I'm sticking with this being absurd. That said, ionization does have it's place in aircraft in terms of controlling attachment or detachment of turbulent airflow over wings.

It can significantly improve fuel consumption by reducing drag. But it is not a viable propulsion source. At least not on Earth for things larger than a meter or so. NelsonMinar on Nov 21, root parent next [—]. You sound arrogant and stupid. You are talking about an article which says "he built the thing and flew it". And you deny that based on your balsa wood experiments? Someone else has done you the favor of posting a video of it flying. One electrode is an aluminum foil skirt, in the shape of a triangle.

High voltage is applied between the foil skirt and the wire. The result is that a downward jet of air is created around and through the middle of the triangle and the lifter flies up off the table. But that is just the barest explanation of how it works. We must go deeper! For a lifter to succeed it has to be extremely lightweight. Typically the propulsion produced by the three sides of the triangle is not even and so to get it stable, all three sides have to be propelling enough to lift their respective sides.

That means that the strongest side is propelling more than it needs to and the weakest side is propelling just as much as it needs to.

The threads holding it down make it look stable at that point. I recall one from Asia I seem to remember it was in Japan but am not sure that was room sized and flew in a large garage or warehouse. The documented record for payload is a 98 gram hexagonal shaped lifter lifting a gram payload using 40kV from a specially made watt power supply.

The lifter flies using ion propulsion. The key is that one electrode acts as a sharp point and the other acts as a smooth edge. The thin wire is the sharp point.

Mine is usually positive. Any sharp point at sufficiently high voltage in air ionizes the air around it. The foil skirt is the smooth edge and is at the opposite polarity, negative and connected to ground in my case. The enhancement I made in my first version was to make the edge of the foil closest to the wire be rounded, resulting in an even weaker electric field. When I tried following the plans of others without the rounding, it was more difficult to get it to lift off.

Having an asymmetric electric field as created by sharp and smooth electrodes is essential to this form of ion propulsion. The positive ions are attracted to the negative skirt. Some get to the skirt and are neutralized, and some collide along the way with neutral air molecules and impart momentum to them.

The neutral molecules then continue in a generally downward direction. The momentum is passed from the ions to the lifter through the electric field during the collisions. Think of the electric field as arms and hands that are physically a part of the lifter and the ions as balls. A ion colliding with a neutral atom is analogous to the ball in your hand smacking into another ball.

When the balls smacking together it pushes your hand in the opposite direction. The same happens to create ion propulsion. Electrons also play a part but with the wire being positive in my example they play more of a part in creating the positive ions than in transferring momentum. Smoke tests show the large mass of air rapidly moving downward through and around the middle of the triangle. Not only did that clearly show the moving air mass, but as you can see in the last photo, I captured a glowing piece of the incense break off and be rapidly carried away in the moving air mass.

Sometimes the experiment is a device suspended along a torsion wire with a small twist produced in the wire. A larger twist is achieved by turning the power supply on and off in time to the movement, but the resulting larger twist is simply the result of resonance, the same as happens when you apply force to a swing at just the right point in its arc to make it swing higher yet.

To make a 0. Some sparks can contain enough current to cause damage to some power supplies, especially PC monitor power supplies. To protect against that use around kiloohms of at least 2 watt rated resistance in series with the input to the lifter. I suspect that the dust was getting positively charged by positive ions getting past the skirt. That would result in the positively charged floor attracting the negative skirt down.

So stay away from dusty surfaces. However, during the collision, some momentum was imparted to the neutral atom in order to make it move, that being the action, and the reaction is the positively charged atom moving in the opposite direction. And that positive ion was in the grip of the electric field which is "connected" to the charges in the electrodes, which are part of the electrodes.

Some propulsion just happened. Most of the positive ions are attracted to the negative electrode where the pick up a negative electron and become neutral atoms again.

But it's possible that some positive ions have enough energy to get away, but the "ion wind" is mostly neutral atoms. How ion propulsion works lifters, ionocraft, ion wind.

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